JP6543119B2 - Stent graft - Google Patents

Description

  The present invention relates to a stent graft which is used by being implanted in a living body.

  Stent grafts mounted in blood vessels, such as arteries, have some degree of unforeseen deformation such as denting or bending due to movement of blood vessels, changes in blood flow, blood pressure, etc. after placement in blood vessels. Shape retention and rigidity (in other words, "hardness") is required, but even if there is expansion / contraction or movement of the blood vessel, "softness" is required so that it can closely adhere to the inner wall of the blood vessel. .

  For example, as a "hard" stent graft that emphasizes shape maintenance, as shown in Patent Document 1, a type in which an elastic metal stent orbits a tubular graft so as to form a zigzag triangular wave (a so-called Z stent is used As shown in U.S. Pat. No. 6,075,014 and U.S. Pat. No. 6,075,015, it is known that the stent has a rhombic mesh structure.

  However, such "hard" stent grafts have the disadvantage that they are difficult to cope with the movement or bending shape of the blood vessel and the adhesion with the blood vessel is poor. As a result, blood may infiltrate into the gap between the stent graft and the inner wall of the blood vessel, and in the case of a Z-stent, the bent corner of the stent may even damage the blood vessel.

  On the other hand, as a stent graft emphasizing "softness", one as shown in Patent Document 3 is known. This stent graft is a tubular graft supported by a stent consisting of a plurality of elastic rings arranged at predetermined intervals.

  However, although such a "soft" stent graft has good adhesion to the blood vessel, the open end may be inadvertently tilted due to the movement of the blood vessel, changes in blood flow, blood pressure and the like. When the open end tilts, a gap is formed between the stent graft and the inner wall of the blood vessel, and blood may infiltrate into the space, or the stent graft may move due to the intruded blood flow. When the open end is inclined, the distance between the one side of the ring and the distance between the opposite side is smaller in the several rings from the open end.

  The replacement of stent grafts and new treatments contribute to the occurrence of the above problems after indwelling.

  Moreover, the hybrid thing which compounded these is disclosed as an idea by patent document 4 and patent document 5. FIG. In these cases, the Z-stent is used only at the end, and a helical stent is used at the middle.

However, it is unclear whether the hybrid stent-grafts described in these Patent Documents 4 and 5 can deliver the stent-graft to the affected area, and it is considered that there are serious problems in practical use. The reason is as follows.
When this stent-graft is contracted radially to be contained in the delivery sheath, the Z-stent is so rigid that it is mainly bent only at the ridges and deforms so that the peaks and valleys of the zig-zag approach. As a result, in the end region reinforced with this Z-stent, the graft is folded longitudinally into folds, and axial deformation can hardly be inhibited by the Z-stent.
On the other hand, when the helical stent is contracted in the radial direction, it is deformed, for example, in a bowl shape, so it must be deformed in the axial direction as well. Thus, in the intermediate region supported by the helical stent, the graft will also deform axially as the helical stent deforms.

Then, when the hybrid stent graft as described in Patent Documents 4 and 5 is folded to contract radially, wrinkles as described below occur.
That is, the helical stent in the middle part is deformed in a bowl shape, so that the graft is also pulled in an axial direction so that the Z stents on both ends try to inhibit this axial deformation of the graft. Do. Therefore, this kind of stent graft will be extremely difficult to fold, and even if it is folded, it is expected that the collapsible contraction diameter will be very large and it may not be able to be accommodated in the delivery sheath.

  Patent documents 4 and 5 do not describe the detailed view at the time of accommodating a stent graft in a delivery sheath to the proof left.

International Publication WO2007 / 022495 International Publication WO 2013/129445 International Publication WO 96/36387 JP, 2011-177520, A Japanese Patent Application Publication No. 2011-502572

  The present invention has been made in view of such problems, and while having the softness, it solves the defect due to it and is indwelled in the body for a significantly longer period of time as compared with the conventional one and functions without hesitation Providing a stent graft is the main objective.

  That is, the stent graft according to the present invention comprises a tubular graft and a plurality of elastic rings intermittently arranged in the axial direction of the tube between both ends of the graft, and the elastic ring is deformed like a hook. And a stent graft which is accommodated in the delivery sheath by folding the graft accordingly, and further comprising an auxiliary elastic wire lower in rigidity than the elastic ring, the auxiliary elastic wire being disposed at an end It is characterized in that it is connected directly or via the graft to a plurality of elastic rings.

With such a structure, even if an axial force due to blood flow or the like is partially applied to the opening edge to incline the opening, the auxiliary elastic wire is between the elastic rings disposed at the opening end. Since the pitch is kept at a predetermined distance, it is possible to prevent an unexpected situation such as tilting of the opening.
Moreover, since the auxiliary elastic wire is lower in rigidity than the elastic ring and is easily deformed when receiving a force from the side surface, it can be flexibly bent according to the bend of the blood vessel.
Thus, blood leakage and accidental migration of the stent graft can be prevented without compromising the features of this kind of "soft" stent graft such as good adhesion to the inner wall of the blood vessel by the elastic ring and shape flexibility. And as a result, after being indwelled in the body, it can function without hesitation for a long time.

  Furthermore, since the rigidity of the auxiliary elastic wire is smaller than that of the elastic ring, and does not significantly inhibit the deformation of the graft when the elastic ring curves like a hook, it is reasonably possible to fold it into a delivery sheath within a small size. it can.

  In order to more surely reduce the inclination of the opening, the auxiliary elastic wire includes a plurality of first wire elements disposed intermittently in the circumferential direction, and each first wire element is disposed at an end. It is preferable that the plurality of elastic rings are connected to cross each other.

  The auxiliary elastic wire may be composed of only a plurality of discontinuous first wire elements, but in that case, there is a risk that the tip of the first wire element may cause a blood vessel to be damaged. In addition, the rigidity of each first wire element must be considerably increased in order to prevent the inclination of the opening, and folds may occur.

  In order to solve this problem at once, the auxiliary elastic wire forms an endless ring that circulates around the graft so that the unevenness is repeated in the direction of the tube axis, and a plurality of second wire elements forming the recess and the protrusion It is preferable that the first wire element connect between the recess and the protrusion.

  This is because the auxiliary elastic wire itself has a three-dimensional structure and a structural rigidity due to the continuation of the first wire element and the second wire element, so the open end supported by the auxiliary elastic wire The shape retention ability and shape recovery function of the above are enhanced, and the tilt prevention function of the opening is increased. In addition, since the auxiliary elastic wire is endless, it is possible to prevent the blood vessel from being damaged. In addition, since the shape maintainability is improved by the three-dimensional structure of the auxiliary elastic wire, the rigidity of the auxiliary elastic wire itself can be minimized, and the folding can be facilitated and the folding diameter can be reduced accordingly. Can also play.

The most deformation site when the elastic ring is folded is near the apex of the curved site, and in particular, if the elastic ring at the most end has resistance to deformation of the curved site, the elastic ring and hence the stent graft folds or expands. Can cause hemorrhoids. In order to avoid this, it is desirable for the said auxiliary elastic wire to be arrange | positioned avoiding this curved site.
As a preferable specific aspect, the thing provided with eight said each 1st wire element and 2nd wire element can be mentioned.

  As a specific arrangement for avoiding the vicinity of the vertex of the curved portion in the elastic ring, the vertex of the curved portion in the elastic ring is positioned between the adjacent convex portion and the convex portion of the auxiliary elastic wire. Can be mentioned.

  In order to reliably avoid that the auxiliary elastic wire is disposed in the vicinity of the apex of the curved portion in the elastic ring, the circumferential length of the second wire element forming the concave avoiding the elastic ring forms the convex second It is preferable that the length set in the circumferential direction of the wire element is set larger.

  In order to improve the three-dimensional structural strength of the auxiliary elastic wire and to prevent accidental damage to the blood vessel by preventing the formation of sharp corners, the first wire element is substantially along the axial direction of the tube. Preferably, the second wire element is smoothly curved from the first wire element and connected to the adjacent first wire element.

  In order to facilitate bending and stretching along the axial direction of the tube, to improve adhesion to the blood vessel, and to prevent unexpected movement in the blood vessel after the stent graft is installed, a plurality of substantially orbiting coils It is preferable that folds be provided on the graft, and the pitch of the folds be set smaller than the pitch of the elastic rings.

  After placement of the stent graft, new damage may occur to the blood vessel corresponding to the rear end (the downstream side of the blood vessel). As a result of intensive studies by the present inventor, the damage can be significantly reduced by setting the outer diameter of the stent graft downstream of the blood vessel to be smaller than the diameter of the middle portion. This effect is particularly pronounced in the treatment of dissociative aneurysms.

In order to facilitate bending and stretching along the axial direction of the tube, to improve adhesion to the blood vessel, and to prevent unexpected movement in the blood vessel after the stent graft is installed, the graft is substantially It is desirable that a plurality of folds to be circulated be provided at a predetermined pitch in the tube axis direction, and the pitch of the folds be set smaller than the pitch of the elastic rings.
For aneurysms and dissections of the aortic arch, placement of a stent graft with a catheter was difficult in the past, and fitting of artificial blood vessels by thoracotomy was common, but it is attached to the aortic arch and the blood vessel wall from the inside A main pipe to be covered and a branch pipe which is branched from the upstream open end of the main pipe and inserted into any one or more arteries (left subclavian artery, left common carotid artery, brachiocephalic artery) branching from the aortic arch If equipped, it is possible to achieve a ground-breaking effect of allowing stent graft placement with a catheter without open chest.
In the present invention, the stent may be constituted not only by the plurality of elastic rings described above but also by an elastic spiral ring.

According to the present invention, since the auxiliary elastic wire keeps the pitch between the elastic rings disposed at the opening end at a predetermined interval, it is possible to prevent an unexpected situation such as the opening being inclined.
Moreover, since the auxiliary elastic wire is lower in rigidity than the elastic ring and easily deformed when receiving a radial force, it can be flexibly bent according to the bend of the blood vessel.
Therefore, it is possible to prevent blood leakage and unexpected movement of the stent graft without damaging the characteristics of this kind of "soft" stent graft such as good adhesion to the inner wall of the blood vessel by the elastic ring and shape flexibility. Use over a year).

  In addition, since the auxiliary elastic wire is lower in rigidity than the elastic ring and does not inhibit the deformation relating to the bending or the expansion of the elastic ring, it can be folded so as to be accommodated in the delivery sheath.

The whole view showing the spread state of the stent graft in a 1st embodiment of the present invention. The partially broken perspective view of the stent graft in the embodiment. The midway view to the folded state of the stent graft in the embodiment. The perspective view which shows the folded state of the stent graft in the embodiment. The expanded view which expand | deployed the stent graft on the plane in order to demonstrate the shape of the auxiliary | assistant elastic wire in the embodiment. Explanatory drawing for demonstrating the method to convey and install the stent graft in the lesion site | part of the blood vessel in the embodiment. Explanatory drawing for demonstrating the method to convey and install the stent graft in the lesion site | part of the blood vessel in the embodiment. Explanatory drawing for demonstrating the method to convey and install the stent graft in the lesion site | part of the blood vessel in the embodiment. Explanatory drawing for demonstrating the method to convey and install the stent graft in the lesion site | part of the blood vessel in the embodiment. Explanatory drawing for demonstrating the stitch in which the stent graft in the embodiment is attached to a conveyance tube. Explanatory drawing for demonstrating the stitch in which the stent graft in the embodiment is attached to a conveyance tube. Explanatory drawing for demonstrating the stitch in which the stent graft in the embodiment is attached to a conveyance tube. The whole view which shows the state which indwelled the stent graft in 2nd Embodiment of this invention in the aortic arch part. The expanded view which developed the stent graft in the plane in order to demonstrate the shape of the auxiliary | assistant elastic wire in other embodiment of this invention. The expanded view which developed the stent graft in the plane in order to demonstrate the shape of the auxiliary | assistant elastic wire in further another embodiment of this invention. The expanded view which developed the stent graft in the plane in order to demonstrate the shape of the auxiliary | assistant elastic wire in further another embodiment of this invention. The whole view which shows the state which indwelled the stent graft in the aortic arch part in other embodiment of this invention.

  One embodiment of the present invention will be described with reference to the drawings.

First Embodiment
The stent graft 100 according to this embodiment is, as shown in FIGS. 1 and 2, a tubular graft 1 (artificial blood vessel) having open ends and attached to the graft 1 to maintain the shape of the graft 1 The stent is provided with the stent 2 and is delivered to the blood vessel B having a lesion such as a thoracic aortic aneurysm or abdominal aortic aneurysm through the catheter 200 (shown in FIG. 5 to FIG. 8) and released. It spreads from the opening force and blood pressure and sticks to the inner wall of the blood vessel B, and the blood vessel B site is covered from the inside to function as an artificial blood vessel B.

  The graft 1 is formed, for example, of a resin sheet having good durability and little tissue reaction into a tubular shape, and as shown in FIG. 2 by partially breaking it, a large number of folds 11 along the circumferential direction are formed. By providing in advance and forming into a bellows shape, bending and bending along the tube axis direction are facilitated. In addition, as a raw material of the said sheet | seat, the textile fabric of a fiber, a nonwoven fabric, a porous sheet etc. can be mentioned. Further, the surface of the sheet constituting the graft 1 may be coated with an antithrombogenic material such as heparin, collagen, acetylsalicylic acid, gelatin or the like.

  The stent 2 is composed of a plurality of elastic rings 21, and these elastic rings 21 extend from one open end of the graft 1 to the other open end of the graft 1 at predetermined intervals (here, substantially constant intervals, but constant). It does not have to be an interval.

  The elastic ring 21 is, for example, an annular ring in which the periphery of a metal core material having a predetermined elasticity is covered with a resin film. The core material is formed by winding an extremely thin metal wire (not shown) in a plurality of layers (multiple). Examples of the material include metals such as stainless steel, tantalum, titanium, platinum, gold, tungsten and alloys thereof. As described above, by forming the core material with a plurality of double-rolled small-diameter metal wires, the durability is improved as compared with the single-roll single-wire type, and partial breakage occurs even if it is broken temporarily. If it only occurs, it has the effect that the function is not lost immediately. The elastic ring 21 may be coated with an antithrombotic material as in the graft 1 described above.

  It is desirable that the elastic ring 21 be attached to the graft 1 so as to be slightly movable. The reason is that when the elastic ring 21 is attached so as to be able to move a little freely with respect to the graft 1, folding and expansion become smoother. On the contrary, if the elastic ring 21 is continuously fixed so as not to allow even a slight movement with respect to the graft 1, it may be difficult to fold or to be small-folded (especially small in radial direction), catheter When coming out of 200, an unexpected situation may occur such as not spreading in the blood vessel B.

  For this purpose, in this embodiment, only a plurality of elastic rings 21 (here, four positions with respect to one elastic ring 12) are sewed intermittently to the graft 1 by, for example, sewing threads P. The details of the sewing position will be described later.

  The elastic ring 21 is attached to the inner circumferential surface of the graft 1. Of course, the elastic ring 21 may be attached to the outer peripheral surface of the graft 1, but if doing so, in order to prevent the graft 1 from being partially separated from the elastic ring 21 and recessed inward It will have to be provided in large numbers. As a result, the freedom of movement of the elastic ring 21 with respect to the graft 1 tends to be impaired, and the production time is also significantly increased. Furthermore, since the elastic ring 21 directly hits the blood vessel B, the blood vessel B may be easily damaged.

  Therefore, in the present embodiment, as described above, the elastic ring 21 is attached to the inner peripheral surface of the graft 1 to minimize the sewn parts and the manufacturing time, and also to prevent the blood vessel B from being damaged.

  However, as for the elastic ring 21 disposed at the upstream end (hereinafter also referred to as front end) and the downstream end (hereinafter also referred to as rear end), like the other elastic rings 21, at most several points on the graft 1 Intermittent sewing alone may cause the graft 1 to be flipped from locations other than the sewing site, resulting in blood leakage.

  Therefore, in this embodiment, as shown in FIGS. 1 and 2, the elastic ring 21 is slidably accommodated in the circumferential direction in an annular accommodating pipe 3 made of a sheet material equivalent to the graft 1, and the accommodating pipe 3 Are continuously joined to the end of the graft 1 by sewing or the like at many places. By this, while allowing some movement of the elastic ring 21 with respect to the graft 1, continuous circumferential attachment of the elastic ring 21 and the graft 1 is realized.

  The stent graft 100 configured in this way is designed to be able to be in a collapsed state with a reduced diameter in order to be accommodated in the delivery sheath (catheter 200).

  In this folded state, all the elastic rings 21 curve in the same direction in the same way, and the graft 1 also deforms accordingly. “Curve-like” here means that as shown in FIG. 3 and FIG. 4, the elastic ring 21 is bent in the direction to be folded in two, and is further bent in the direction to be folded in the two, Means to transform so that four appear alternately. In the following, in the elastic ring 21, a certain range that forms a peak and a valley by curving when it is deformed into a bowl shape is referred to as a curved region W, is positioned between the curved regions W, and a degree of curvature is The small part is called intermediate part M.

  As can be seen from FIGS. 3 and 4, in the process of deformation of the elastic ring between the expanded state and the folded state, the curved portion W (especially, the peak of the peak and the peak of the valley) is most deformed On the other hand, the intermediate portion is less deformed.

  Therefore, when the graft 1 is connected to the elastic ring 21 at a place where the deformation is large, the graft 1 must be deformed following the large deformation of the elastic ring 21, so that the resistance for deforming the elastic ring 21 is growing. As a result, the stent graft 100 may not be easily folded, may not expand, may not be sufficiently reduced in diameter even after being folded, or may be damaged due to an excessive force acting on the graft 1.

Therefore, in this embodiment, the graft 1 is sewn to the elastic ring 21 only at the smallest deformation point in the elastic ring 21, that is, at the center of the middle portion M (center between the peak of the peak and the peak of the valley). In order to solve the above problems. However, as described above, the elastic rings 21 at both ends are not limited thereto.
Next, a method of delivering the stent graft 100 to a lesion site will be described with reference to FIGS.

  First, the stent graft 100 is attached to the delivery tube 300 inserted into the inside, and the stent graft 100 is folded in this state and accommodated in the distal end portion of the catheter 200. The transfer tube 300 is made of hollow resin, and is set so that the tip end of the transfer tube 300 protrudes from the tip of the catheter 200.

  Next, the catheter 200 containing the delivery tube 300 and the stent graft 100 is inserted into the blood vessel B, and the distal end of the catheter 200 reaches the lesion site as shown in FIG.

  Next, as shown in FIGS. 7 and 8, only the catheter 200 is pulled back to release the stent graft 100 in the blood vessel B. As a result, the stent graft 100 is expanded from the folded state to the expanded state in which the diameter is expanded by its expansion force (elastic return force of the stent 2) and the blood pressure, and the stent graft 100 closely adheres to the inner wall of the vascular lesion site.

Finally, as shown in FIG. 9, the stent graft 100 in the expanded state is removed from the delivery tube 300, and then the delivery tube 300 and the catheter 200 are recovered.
In FIGS. 8 and 9, the elastic ring 21 is not completely expanded but slightly bent, but even when the blood vessel B is expanded due to a change in blood pressure or the like, the graft 1 can be reliably formed on the inner wall thereof. It is for making it adhere. Therefore, the diameter of the elastic ring 21 is set to be slightly larger than the normal inner diameter of the blood vessel B.

  Here, the attaching / detaching structure for attaching / detaching the stent graft 100 mentioned above to the conveyance tube 300 is demonstrated. In this attachment / detachment structure, as shown in FIG. 10 to FIG. 12 etc., the locking wire 301 inserted through the inside of the transfer tube 300, the window 302 provided in the transfer tube 300, and the base end are fixed to the transfer tube 300. Provided at the opening edge of the stent graft 100 and a plurality of attached (here four, but only two attachment / detachment strings 303 are shown in FIGS. 10 and 11 for simplicity). The plurality of (in this case, four) hook holes 304 are used.

  The locking wire 301 is a steel wire, and can be advanced and retracted in the transport tube 300 by pushing and pulling it at hand. The window 302 is formed by cutting away a portion of the transfer tube 300, and the internal locking wire 301 is exposed from the window 302.

The attachment / detachment string 303 is a ring formed at least at the tip (here, the whole is a ring), and the base end thereof is in the vicinity of the window 302 in the transfer tube 300 (here, from the window 302). Also fixed to the hand side).
The hook holes 304 are formed by attaching a thread in an annular shape to the front end opening edge of the stent graft 100.
Next, the process of attaching the stent graft 100 to the delivery tube 300 will be described.

First, as shown in FIG. 10, the detachable string 303 is passed from the tip to hook holes 304 provided at four places at the opening edge of the stent graft 100.
On the other hand, the lock wire 301 is operated to expose the tip of the window 302 provided in the transfer tube 300.

  Next, as shown in FIG. 11, the front end ring of the detachable cord 303 passing through the hooking hole 304 is inserted into the window 302 and hooked on the front end of the locking wire 301. After hooking all the detachable cords 303, as shown in FIG. 12, the locking wire 301 is drawn out so that the tip passes through the window 302 and reaches the back of the transfer tube 300 (further, the tip). In this way, the tip ring of the detachable string 303 passing through the hooking hole 304 is locked in the middle of the locking wire 301 exposed from the window 302 of the transfer tube 300, and the stent graft 100 is transported via the detachable string 303. It will be attached to the tube 300.

  On the other hand, in order to remove the stent graft 100 from the delivery tube 300, the lock wire 301 is pulled so that its tip is located on the proximal side of the window 302. As a result, the distal end ring of the detachable string 303 is detached from the locking wire 301, and the stent graft 100 can be detached from the delivery tube 300.

  The hooking hole 304 is provided at the middle portion M in the folded state (more specifically, in the middle of the middle portion M). If it is this place, the distance from the shaft does not change in the folded state or the expanded state, and the four detachable strings 303 can be always kept in the equal tension state. In the case of two detachable straps 303, the hooking holes 304 may be arranged at the top of the curved portion W.

In addition, before collecting the transfer tube 300 and the catheter 200, a balloon (not shown) is guided to the transfer tube 300 to be transferred into the stent graft 100 and expanded to ensure adhesion of the stent graft 100 to the inner wall of the blood vessel B. It does not matter.
The above is the specific structure of the stent graft 100 and the method for transporting and installing the same.

In this embodiment, as shown in FIG. 1 and the like, the metal auxiliary elastic wire 5 thinner than the stent 2 and smaller in rigidity is placed on the end outer peripheral surface (at least the front end outer peripheral surface) of the graft 1. It is attached (stitched) so as to go around.
The attachment (sewing) pitch here is smaller than the pitch between the elastic rings.

I will explain in detail.
The auxiliary elastic wire 5 has an endless annular shape which circulates around the graft 1 while the unevenness is repeated, as shown in the perspective view in FIG. 1 to FIG. 4 and the developed view in FIG. It comprises eight second wire elements 52 forming the recess (b) and the protrusion (a), and eight first wire elements 51 connecting the recess (b) and the protrusion (a).

  Here, the first wire element 51 extends substantially along the axial direction of the tube, and is disposed so as to intersect a plurality of (two to five) elastic rings 21 located at the end. . And the space | interval between the adjacent 1st wire element 51 is not constant, and it is comprised so that a wide space | interval and a narrow space | interval may be alternately repeated.

  The second wire elements 52 are curved so as to slightly expand toward the opening side between the tips of the closely-spaced first wire elements 51, that is, between the ends on the opening side of the graft 1 The convex portion (a) is formed, and between the proximal ends of the widely spaced first wire elements 51, the concave portion is curved and bridged so as to slightly expand toward the opposite opening side. (B) is formed.

  Then, the curved portion in the stent 2 is a portion between adjacent first wire elements 51 and between the tips of which the second wire elements 52 are not bridged, that is, between the widely spaced first wire elements 51. The auxiliary elastic wire 5 is disposed so as to be located at the portion W.

  Furthermore, in this embodiment, the rear end outer diameter disposed downstream of the blood vessel B is set smaller than the diameter of the middle portion, and a gap is formed between the outer periphery of the rear end opening of the stent graft 100 and the blood vessel B. It is made to occur.

  According to the stent graft 100 having the above-described configuration, in the expanded state, the auxiliary elastic wire 5 has a three-dimensional structure so as to exhibit the shape maintaining function, and the distance between the elastic rings 21 at the opening does not change. Since maintenance is performed, it is possible to suppress the inclination of the opening relative to the tube axis.

Chew more and explain.
Although it is difficult to suppress the inclination of the elastic ring 21 itself although the expansion force in the radial direction can be obtained with the elastic ring 21 alone, an unexpected force is caused by the blood flow, the movement of blood vessels, etc. when installing a stent graft. As a result, the several elastic rings 21 arranged in the opening can be inclined, for example, from the intended position perpendicular to the axial direction of the tube. As a result, the opening portion is inclined and a gap is formed between the blood vessel B and the blood, which may cause leakage of blood or unexpected movement of the stent graft.

  On the other hand, according to this stent graft 100, as described above, the auxiliary elastic wire 5 is attached across the plurality of elastic rings 21 in the opening portion, and supports so that the distance between the elastic rings 21 does not change. Therefore, the inclination of each elastic ring 21 is suppressed, and the opening is maintained so as to be substantially perpendicular to the tube axis direction.

  Further, since the auxiliary elastic wire 5 is an endless annular three-dimensional structure in which irregularities are formed in the tube axis direction in the expanded state, the shape maintenance property attributed to the structure is high, and the shape maintenance property is high Since the open end of the stent graft supported by the elastic wire 5 also has high shape maintenance, it can be said that it becomes difficult to tilt.

  On the other hand, as described above, while the auxiliary elastic wire 5 can improve the shape maintainability in the expanded state to prevent the inclination of the opening, it also has an effect of hardly promoting difficulty in folding. The shape can be maintained to a certain extent by the above three-dimensional structure, so that the rigidity of the auxiliary elastic wire 5 itself may be minimal, and for example, it is very flexible, half or less of the elastic ring 21 as in this embodiment. It is because a material can be adopted.

Regarding ease of folding, in this embodiment, the ease is also ensured by the arrangement of the auxiliary elastic wire 5.
The reason is explained in detail.
As described above, the elastic ring 21 is most deformed at the curved portion W (four places). Therefore, if the deformation of the curved portion W is inhibited, the folding / deploying of the stent graft 100 can not be smoothly performed.

  Thus, what inhibits the deformation of the elastic ring 21 is the graft 1 near the elastic rings 21 at both ends, that is, the end of the graft 1, and the deformability of the graft 1 in this part is the deformation of the elastic ring 21. It will be greatly related to the ease.

  Specifically, the elastic ring 21 except for both ends is only sewed intermittently to the graft 1 at four places, and the sewn place is an intermediate part M where deformation due to folding is small. Thus, the elastic ring 21 deforms substantially independently of the graft 1. Therefore, the graft 1 except for the both ends can not be a large resistance when the elastic ring 21 is deformed.

  On the other hand, the elastic rings 21 at both ends are attached to the entire circumference of the graft 1 as described above, and the graft 1 deforms following the deformation. Therefore, as described above, the deformability at the end of the graft 1 is largely related to the deformability of the elastic ring 21.

  Among them, the deformability of the end portion of the graft 1 at the curved portion W having a large deformation due to the folding strongly influences the deformability of the elastic ring 21. On the other hand, even the end portion of the graft 1, the graft end portion at the intermediate portion M hardly contributes to the ease of deformation since the elastic ring 21 is not deformed so much in the first place.

  In this embodiment, in the portion where the graft 1 has to be deformed following the elastic ring 21 and the portion where the deformation is large, ie, the curved portion W at the end of the graft 1, the auxiliary elasticity is Since the wire 5 is not disposed, the auxiliary elastic wire 5 hardly inhibits the deformation of the elastic ring 21.

  In this embodiment, the portion of the auxiliary elastic wire 5 disposed at the end of the graft 1 is only the convex portion (a) of the second wire element 52, and this is a curved portion of the elastic ring 21. It is disposed in a region corresponding to the intermediate portion M while avoiding W.

  As described above, according to the stent graft 100 according to the present embodiment, since the shape maintainability of the end in the expanded state is improved by the auxiliary elastic wire 5, the stent graft 100 of this type using the elastic ring 21 is obtained. It is possible to prevent unexpected inclination of the opening which is the defect without inhibiting the flexibility and the adhesion to the inner wall of the blood vessel B, and it is possible to function without hesitation for a long time after being placed in the body Become.

Moreover, since the shape, the arrangement and the rigidity of the auxiliary elastic wire 5 are carefully set to secure the ease of deformation between the expanded state and the folded state, it can be finely folded, for example, the ease of operation It is possible to maintain and expand smoothly and reliably in the blood vessel B.
In addition to this, according to this stent graft 100, the following effects can also be obtained.
Since the auxiliary elastic wire 5 has an endless annular shape and does not have a tip, the blood vessel B is less likely to be damaged.

  Since the graft 1 has a bellows-like shape and is flexible, it can easily follow the movement of the blood vessel B (in particular, expansion and contraction) and can be firmly adhered to the inner wall of the blood vessel B. As a result, it is possible to prevent the stent graft 100 from moving unexpectedly from the initial installation site.

  After placement of the stent graft 100, the blood vessel B corresponding to the rear end (the downstream side of the blood vessel B) may be newly damaged. The frequency is higher than the tip and middle of the stent graft 100, and the solid cause is unknown. However, as a result of intensive studies by the present inventor, the damage is largely reduced by setting the outer diameter of the rear end portion of the stent graft 100 smaller than the inner diameter of the corresponding blood vessel B as described above. This effect is particularly pronounced in the treatment of dissociative aneurysms.

  Since the front end opening edge of the stent graft 100 is attached to the delivery tube 300 as a parachute line by the four detachable cords 303, the front end opening of the stent graft 100 tends to be perpendicular to the axis of the blood vessel. It can be properly installed properly.

Second Embodiment
Next, a second embodiment of the present invention will be described.

  The stent graft 100 according to the present embodiment is disposed so as to cover the (distal) arch aortic aneurysm A from the inside.

This will be described specifically.
As shown in FIG. 13, this stent graft 100 is attached to the aortic arch B and covers the aortic aneurysm A from the inside, and is branched from the upstream end of the main pipe 101 and inserted into the left subclavian artery B1. And the branched pipe 102.

  The basic structure of the main pipe 101 is the same as that of the single-tubular stent graft in the first embodiment. That is, the main pipe 101 is disposed at the first graft 1A, a plurality of elastic rings 21A attached to the first graft 1A, and the upstream opening end and the downstream opening end of the first graft 1A. The auxiliary elastic wire 5 provided is provided.

  In the main pipe 101, a resin elastic wire 9 extending along the axial direction of the pipe is attached to the outer peripheral surface on the opposite side to the branch pipe 102, and the contraction force of the resin elastic wire 9 The main tube 101 is configured to curve along the aortic arch B.

  The main tube 101 has its upstream end located between the left subclavian artery B1 and the left common carotid artery B2 and extends downstream from there along the aortic arch B, the downstream end of which is aortic aneurysm A It is arranged to be more downstream.

The branch pipe 102 comprises a second graft 1B and a plurality of second elastic rings 21B attached to the second graft 1B. The auxiliary elastic wire is not provided at the tip of the branch pipe 102.
The proximal end of the branch pipe 102 is attached between the wide first wire element 51 of the auxiliary elastic wire 5 disposed at the upstream open end of the main pipe 101, that is, at the curved portion W. The curved portion W to which the branch pipe 102 is attached is not a portion bent so as to protrude to the distal end side in the folded state, but a portion bent so as to be recessed.
Explain the reason. As described in paragraph 0049, the open end of the main tube 101 is in a slightly bent state when deployed in the aortic arch B. At this time, the curved portion W is slightly curved due to the wrinkles in the folded state. More specifically, among the four curved portions W, the opposing pair protrudes toward the tip end, and the other pair is recessed. Since the branch tube 102 is attached to one of the pair of concave curved portions W, the other concave curved portion W is positioned on the inner wall of the aortic arch B, which is the most curved side. If this arrangement is reversed, that is, the protruding curved portion W is positioned on the inner wall of the small bay side, the protruding curved portion W can not follow the bending of the inner wall of the small bay side, and can be curled up from the inner wall of the small bay side Sex occurs. In order to reduce this possibility as much as possible, the branch pipe 102 is attached to the above-mentioned curved portion W.

Therefore, according to this embodiment, the effect of the auxiliary elastic wire 5 is particularly remarkable.
Explain the reason.
In the case of (distal) arch aortic aneurysm A, the main tube 101 covering the aortic aneurysm A is because the left subclavian artery B1, the left common carotid artery B2 and the right balvocapsular artery B3 are branched one after another from immediately upstream thereof. It can not be stretched long on the upstream side. Moreover, the aortic arch B is strongly bent. Then, the end of the main pipe 101 must be placed at the site H where the blood vessel is strongly bent.

  Placing the end of a conventional "soft" stent-graft at these bends H makes the opening more inclined and blood leaks from it, resulting in the stent-graft being displaced. On the other hand, in the case of a "hard" stent graft, it is difficult in the first place to fit the bending site H. Therefore, conventionally, there has been a situation that placement of a stent graft by a catheter is extremely difficult for aortic aneurysm and aortic dissection at this site.

  On the other hand, the stent graft 100 according to the present embodiment is “soft”, so that it fits into the blood vessel corresponding to the bending portion H and the auxiliary elastic wire 5 can surely prevent the inclination of the open end.

  Moreover, in this embodiment, since the branched pipe 102 branched from the main pipe 101 enters the left subclavian artery B1 and functions as a so-called positioning member, the stent graft 100 corresponds to the blood vessel shape of the patient who was scrutinized in advance. By being shaped, the blood vessel can be fitted more reliably.

  For these reasons, according to the stent graft 100 according to the present embodiment, it is expected that the archival effect that the stent graft 100 can be indwelled by a catheter with respect to the arch aortic aneurysm A without open chest can be expected. Be

The present invention is not limited to the above embodiments.
For example, the auxiliary elastic wire may be attached to the rear end opening. In the second embodiment, the auxiliary elastic wire may be attached to the open end of the branch pipe.

Although it is a shape of the said auxiliary | assistant elastic wire 5, as shown in FIG. 14, the 1st wire element 51 may not be completely parallel with a pipe axis like the said embodiment, and may be slightly oblique. Further, as shown in FIG. 15, the first wire element 51 may not be straight, and may be slightly curved.
In addition, the narrow portions of the adjacent first wire elements may be configured to correspond to the curved portions, or the first wire elements may be provided at equal intervals in the circumferential direction.
The auxiliary elastic wire is sewn to the graft in the above embodiment, but may be attached directly to the elastic ring without attaching to the graft.

Furthermore, the auxiliary elastic wire 5 may not have an endless annular shape. For example, as shown in FIG. 16, the auxiliary elastic wire 5 may be a discontinuous one comprising a plurality of linear or slightly curved wire elements 53 extending substantially in parallel with the tube axis direction. In this case, it is preferable to arrange the elastic wire element 53 so as to avoid the curved portion W, and in this case, four wire elements 53 may be provided.
In the said embodiment, although the auxiliary | assistant elastic wire 5 was attached to the outer peripheral surface of the graft 1, you may attach to the inner peripheral surface of a graft.
The stent may be helical.

The rear end opening edge of the stent graft may be provided with the same attachment / detachment structure as the front end opening edge. In that case, a second transfer tube for locking the tow cord (second tow cord) is passed through the catheter 200, a window is provided in the second transfer tube, and the second locking wire is inserted inside. The second tow string may be hooked.
In the second embodiment, a stent graft with a single branch tube inserted into the left subclavian artery is used, but in addition to that, for example, when the aneurysm extends to the left common carotid artery or the right baltococcal artery, it corresponds correspondingly It may be a two-branch or three-branch stent graft. A bifurcated stent graft 100 is shown in FIG.
Further, in the second embodiment, the branch pipe was extended from the upstream open end of the main pipe, but when the aneurysm is in the ascending aorta, the branch pipe is extended from the downstream open end of the main pipe Is preferred.
Even in the above case, since the upstream end or the downstream end of the main pipe is placed in the aortic arch where the curve is strong, the auxiliary elastic wire provided at the end sufficiently functions to exhibit the same function and effect. Be done.
It goes without saying that the present invention can be variously modified without departing from the scope of the present invention.

100 ... stent graft 1 ... graft 2 ... stent 21 ... elastic ring 5 ... auxiliary elastic wire 51 ... first wire element 52 ... second wire element 200 ... catheter ( Delivery sheath)

Claims (10)

It comprises a tubular graft and a plurality of elastic rings intermittently arranged in the axial direction across the ends of the graft, and the elastic ring is deformed like a hook and the graft is folded accordingly. A stent graft that is contained within the delivery sheath by
A stent graft, further comprising an auxiliary elastic wire lower in rigidity than the elastic ring, wherein the auxiliary elastic wire is arranged only at one or both ends of the graft.   The auxiliary elastic wire comprises a plurality of first wire elements disposed intermittently in the circumferential direction, and each first wire element is connected so as to cross a plurality of elastic rings disposed at an end. The stent graft according to claim 1, characterized in that:   The auxiliary elastic wire is in the form of an endless ring that wraps around the graft so that the unevenness is repeated in the direction of the tube axis, and the plurality of second wire elements forming the recess and the protrusion, the recess and the protrusion The stent graft according to claim 1, comprising the first wire element connecting the two.   The stent graft according to claim 1, wherein the auxiliary elastic wire is disposed so as to avoid the vicinity of the apex of the curved portion in the elastic ring at both ends. The stent graft according to claim 3, wherein eight first wire elements and eight second wire elements are provided.   The stent graft according to claim 5, characterized in that a vertex of a curved portion of the elastic ring is positioned between adjacent convex portions and convex portions of the auxiliary elastic wire. The stent graft according to claim 6, wherein the circumferential length of the second wire element forming the recess is set larger than the circumferential length of the second wire element forming the protrusion.   The first wire element extends substantially along the axial direction of the tube, and the second wire element is smoothly curved from the first wire element and connected to the adjacent first wire element. The stent graft according to claim 3.   The stent graft according to claim 1, wherein the diameter of the opening disposed on the downstream side of the blood vessel is set smaller than the diameter of the middle portion. The bifurcated tube which is attached to the aortic arch and covers the aortic aneurysm from the inside, and which is branched from the graft and inserted into a blood vessel branching from the aortic arch. Stent graft.